Fixes#56, and adds netherbrick rails (for consistency with MTG) if the fences API is found.
Using the MTG fence system adds interop between different fence types, and support for the "Tall fences and walls" option.
I've left the nether's register_craft() call unchanged, it overrides the recipe that default.register_fence() registers, granting 6 fences per crafting instead of MTG's 4.
* Add Netherrack slabs and walls
Also adds deep netherrack stairs, and deep nether brick stairs, slabs, inner stairs and outer stairs.
Adds 9 new nodes in total.
* Treasure: Nether pickaxe takes 10x less wear damage when mining netherrack
cracky-3 mining time of Nether pickaxe reduced from 0.4 to 0.3 to mine netherrack faster.
maxlevel of nether pickaxe dropped from 3 to 2 to increase wear damage with non-netherrack nodes.
* Treasure: Nether staff of light
Adds "Nether staff of Light" and "Nether staff of Eternal Light"
One is limited to 60 uses, and the other has unlimited uses but the glowstone it creates will only last for 40 seconds.
There are no crafting recipes as I hope these to eventually be treasure that can be found in the nether.
See the pull request (#50) for more discussion
Adds a magma oceans region to the nether outside the existing nether caverns, which can be reached via tunnels.
Other misc changes:
* chatcomment nether_whereami, a debug aid for knowing which perlin-noise region you are in
* Nether ores no longer obtainable on the ceiling
* Move crafts into crafts.lua
* Add steam to lava cooling, and play bubbling lava upon death by lava
* Add cracked netherbrick
a decorative node which can only be obtained from dungeons or structures
I encourage someone to improve or replace the cracked netherbrick texture. For copyright purposes it's currently a derivative work (by me, 2020) from nether_brick.png, which is licensed under CC BY-SA 3.0 by PilzAdam, so it can fall under the "All other media" PilzAdam's credit in readme.md rather than need its own entry.
The round ones look nice and cartoony, but not the right art direction for Minetest Nether.
Making use of the existing default_item_smoke.png is also a close contender for smoke puffs, but it's not translucent and I think the roundness of it reduces how much the puffs form into plumes.
(new animation by Extex101)
The original texture is now "nether_portal_alt.png", and used to provide a "nether:portal_alt" node, which is used/demoed by the Surface-portal as the original animation still has a "it's full of stars" charm coming out when used for lighter coloured portals.
Improvements found while using the portals API in another mod (cloudlands):
* remote_portal_checkup() will check the whole portal and frame for mapgen overwrites.
* Allow find_realm_anchorPos() to return nil if no realm location could be found (portal will fail to ignite).
* Allow create_book_of_portals() to be invoked [indirectly] by other mods.
Also lowers nether_book_close.png to be 4bpp
